Irrigation Systems Get Smart

It happens the same way every year. On the first 90-degree day of summer, lawn lovers and garden gurus alike crank up their irrigation systems to save their plants from the drying heat.And then they forget all about having turned them on.

When the temperatures drop back down to a more comfortable 70-degree range, the sprinklers are still spurting out water like it’s the dead of summer. But an overwatering situation is almost as bad as drought, according to lawn-care experts.

“Just as no water can be detrimental to plants during the summer, having too much water can also have a negative impact on plant material,” Richard Silverman, owner of Greenlawn-based Rain Rich, explained during a recent telephone interview. “It’s that whole concept of ‘more is better.’ Sometimes, it’s not.”

Today, “smart”—or water conserving—irrigation systems eliminate the guesswork, Mr. Silverman said. And the technology now available has grown exponentially.

“I’ve been doing this for over three decades and it’s unbelievable how things have improved over the years,” he said. “You can really get down to the nitty-gritty of watering per minute, per zone and having different minutes on different zones. You can have multiple programs, so you can have a lawn zone that needs water every day, once a day, and plant material that may only need watering once or twice a week.”

This type of technology, called a weather station, first appeared on golf courses, according to Robert Boyle of RB Irrigation in Westhampton Beach. In the past three years, the 6-inch, flower-pot-sized sensor—which collects data on temperature, wind speed and humidity for the specific property, and then applies it to each landscaped zone’s conditions, such as soil type and plant material—has become affordable for the average homeowner and is mountable on the side of a house, he said during a telephone interview earlier this month.

The sensors typically range from $400 to $700, Mr. Boyle reported. Homeowners considering the option should keep in mind though that a fully installed sprinkler system can cost between $2,500 and $25,000, Mr. Silverman said, depending on the type of sensors and the ratio of lawn to landscaped gardens. The latter usually require more sprinkler heads or drip irrigation, which distributes water directly to the roots and is, arguably, the most efficient irrigation system.

“Typically, you try to emulate Mother Nature to some degree,” Mr. Boyle said. “You try to water less often with deeper watering. Having a beautiful landscape doesn’t necessarily mean using a lot of water.”

Generally, and depending on the landscaping, the aim is to deliver about an inch of rainfall per week during the summertime, Mr. Silverman said, which for an acre of lawn equates to about 27,000 gallons for the season. It is best to water between 2 and 4 a.m., with cycle completion by 6 a.m., he said, when there is less wind and better water pressure.

Watering times are especially important during a drought, Mr. Boyle said. After all, irrigation uses more water than any other household appliance, he added.

“Long Island gets four times the amount of rain than it needs to fill the aquifers. It’s not like we’re short on water,” he said. “But what happens is, the purveyors, or the water companies, only have the ability to pump so much water out of their system at any given time. So when you’re three, four weeks into a drought and everybody’s trying to water their lawns, they’re making it very difficult for the water districts to keep up with the demand.”

Homeowners who have elected to save their devastated landscapes following Superstorm Sandy instead of gutting and starting anew will be using more water this summer, regardless of their smart irrigation systems, Mr. Silverman said. That is the only way to save their plants, he continued.

“When salt water enters the cells of the plants, it causes the cell wall to expand and rupture,” he said. “Just like if you drank salt water. Because there’s sodium chloride in the cell, the cell needs to take on more water in order to dilute that sodium chloride, and in doing so, actually repairs the cell walls.”

The best solution is to flush the soil by irrigating more frequently, he said, which will also wash any residual salt off the trees and flowers.

“Plants are very resilient,” Mr. Silverman said. “They can take a lot of abuse and come back. I’ve heard it may take one to several seasons to recover. I think they’ll be all right.”